


Gathering Data

by revampired



Category: Yuri!!! on Ice (Anime)
Genre: ...Kinda, Alternate Universe - Merpeople, Fingerfucking, Gratuitous Liberties Taken With Fish Anatomy, Human/Merman Sex, Intersex/Gender Fluid Mer, M/M, Marine Biologist Yuuri Katsuki, MerMay, MerMay 2018, Merman Victor Nikiforov, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Victor Nikiforov, Plot What Plot/Porn Without Plot, Protective Katsuki Yuuri, Vaginal Sex, basically yuuri finds victor the merman on a beach and they have sex, but like for science!
Language: English
Status: Completed
Published: 2018-05-28
Updated: 2018-05-28
Packaged: 2019-05-14 12:23:36
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,581
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14769551
Author URL: https://archiveofourown.org/users/revampired/pseuds/revampired
Summary: Marine biologist Yuuri Katsuki accidentally learns way more about mer anatomy than he intended.





	Gathering Data

**Author's Note:**

> Lmao please don't take this fic too seriously it's just fun PWP that I wrote for Mermay. There's a bit of worldbuilding in the end notes for stuff that didn't make it into the fic because it was getting toooooo long. I meant to write a part 2 but then I got super busy and also kinda sick, so that didn't happen. :P 
> 
> Just a warning there's a teeeeeeny bit of blood in this (Yuuri gets scraped on some of the rocks) but it's not at all violent.
> 
> Please enjoy this fic! Leave a comment if you did, pls validate my weird porn :D

There’s a _merman_ lying on the beach.

Yuuri swallows, staring at the beautiful creature washed up on the shore, lying languidly over a nest of seaweed. They’re rarely seen outside of deep water, away from rocky outcroppings humans have barely managed to map in the last half-century.

Sure, the island they’re on is remote, a little tropical paradise in the Pacific – but it’s inhabited, and has been for centuries. Sightings of mer by humans are exceedingly rare, sightings on inhabited land even moreso. For most of human history, mer were thought to be a myth, a symptom of sea-sick hallucinations or just old tales sailors told each other to pass the time. Then, as technology developed, deep-sea divers found evidence of them, boats docked in every conceivable bit of rock sticking up above the surf.

And now-

This one, likely a male from the lack of developed breasts – very little is known about mer reproduction, but the evidence of male-like broad shoulders and thicker arms and female-like full breasts serves as a classification for now – toys with a strand of seaweed, popping a scuttling crab into his mouth and crunching down. There’s a strange expression on his face, something almost despondent.

Yuuri pulls out his little notebook and writes, _very strong jaws, capable of crushing crab shells_.

They – Yuuri, Celestino, and Phichit, the little research team based out of Kyoto University – are here to study mating habits of native cetaceans. Yuuri could never imagine, in his wildest dreams, that he’d ever get the opportunity to study a mer – even from afar, the little tidbit he’s learned about the crab is invaluable.

He’s truly beautiful, this mer. His scales are a shimmering, iridescent pearl, barely lighter than the milky white of his skin. His hair, too, is pale silver, falling in shimmering, wet strands down his back and arms. Yuuri wonders what mer hair is made out of that keeps it from tangling and cracking on exposure to salt water, like human hair does.

A dusting of red brushes the mer’s shoulders and cheeks and nose, and Yuuri frowns, noting that curiously. A lightly sunburnt mer – how strange. That can’t be an evolutionary advantage.

He takes out his phone and takes a photo, the camera clicking loudly against the sound of the surf. Yuuri freezes, phone out, shifting as quietly as he can behind a rock.

Suddenly, the mer turns, and Yuuri finds himself pierced by a pair of luminous blue eyes. The mer’s eyes widen, and Yuuri freezes, and for a moment the pair stare at each other, petrified.

“Wait,” Yuuri calls, desperately, picturing the mer disappearing back into the ocean and with it Yuuri’s chances of a breakthrough scientific discovery.

Instead, though, the mer makes a stricken expression and flops off the nest of seaweed, behind a rock, and covers himself with fat pods of seaweed. Yuuri blinks. The pearly white tail is still visible against the yellow sand, as is the rise and fall of the mer’s chest, under his protective layer of seaweed – and if Yuuri had to guess, he’d say the mer’s breathing seemed a little labored.

There must be a reason the mer didn’t just disappear into the sea. Yuuri gulps, clambering over wet sand and jagged rocks, to where the mer is hiding.

“Hey,” Yuuri whispers, staying arms length from the mer – mythical and beautiful or not, he’s still a potentially hostile wild creature. “Hey. I’m not gonna hurt you.”

The mer stiffens, peering up from under a curtain of silver hair and seaweed.

“Do you… Do you understand me?” Yuuri asks, uncertainly, kneeling so as not to seem threatening.

The mer pauses, gaze bright and intelligent, taking in Yuuri’s face, his khaki swimwear, his stiff hiking boots, his hat to keep off the sun. Then, slowly, he nods.

Yuuri somehow didn’t expect that answer. He starts, staring deep into the mer’s sky blue eyes. “You can understand me? Understand humans?”

The mer looks confused, biting his lip with teeth that Yuuri notes are very sharp – but somehow the skin doesn’t break. He nods again, uncertainly.

“Oh,” Yuuri says, lamely. “Oh. Cool! Can you… Can you speak?”

The mer shakes his head.

“Hm,” Yuuri murmurs, taking out his note book and clicking his ball point pen open, “Can no mer speak? Or is it just you?”

The mer’s brow furrows, and he tentatively holds up one finger.

“Just you?” Yuuri clarifies.

The mer shakes his head. Yuuri blinks, confused – and then he realizes.

“Oh!” he gasps, “You meant answer number one, no mer can speak.”

The mer nods. Yuuri scribbles that down, noting that the mer pouts as he turns his attention away from him.

“How’d you learn English? Do different mer know different languages? Is English the lingua franca among mer as well?” Yuuri rattles off, staring at the mer expectantly.

The mer just blinks back at him, looking annoyed, and Yuuri realizes why a second later.

“Ah, right,” he says, laughing sheepishly and flushing in shame, “Right. Can’t speak. Hm – can mer write?”

The mer brightens, nodding. He scribbles pairs of lines into the sand, little figures almost like hieroglyphics. Yuuri droops in disappointment.

“Ah,” he says, softly, “So you have your own language, but can’t write in English.”

The mer nods again, lips pressed into a thin line. Yuuri is halfway through writing down his observations when a pair of hands with very sharp, completely opaque nails grabs his notebook and tosses it with immense strength halfway across the beach.

Yuuri yelps and jumps back, unaware how close he’d been getting to the mer in his excitement. When he meets the mer’s gaze, though, he doesn’t find the feral toothy growl of an enraged animal – in fact, the mer looks almost _pouty_.

The mer looks from Yuuri to the notebook, now far out of reach, and turns away from him with a huff. Clumps of seaweed fall from his head and shoulders, and Yuuri wonders if seaweed isn’t how he keeps his hair so glossy.

The reason for the mer’s behavior clicks almost instantly, and when he understands, Yuuri can’t help but laugh. The mer stiffens, body language very clearly conveying offense.

“I’m sorry,” Yuuri soothes, daring to get just a little closer, “I’m sorry. That was very rude of me, taking notes instead of paying attention to you.”

The mer relaxes a little, tossing an obstinate glance over his shoulder.

Yuuri bites back another laugh, settling onto his knees in the sand, and says, “It’s just that mer are so interesting to me. _You’re_ so interesting to me. I’d like to get to know you a little better.”

The mer shifts, facing Yuuri again, pressing his lips into a thin line.

Yuuri holds out his hand, not sure if the mer knows what that means but deciding to risk it anyway. “I’m Yuuri,” he says. “My name is Yuuri.”

The mer takes the hand, pinching it awkwardly between his thumb and two fingers, and jerks the hand up and down. So, Yuuri notes, he’s clearly familiar with some aspects of human culture – that was definitely an attempt at a handshake.

“Do you have a name?” Yuuri asks.

The mer nods. Yuuri _hmms,_ wondering how he can ask the mer’s name, how the mer could tell him.

“Could I – could a human say your name?” Yuuri asks.

The mer shakes his head.

Yuuri taps his chin, thoughtfully. “Would it be alright if I gave you a nickname? So I have something to call you?”

The mer seems to consider this, staring at Yuuri thoughtfully. Then, slowly, he nods.

“Okay,” Yuuri says, “Okay. Hm. How about-” he scrambles for a nickname, something to call the mer. “Victor?”

Yuuri winces almost as soon as he says the name. Victor – lovingly called Vicchan – was his _dog_. His now dead dog. He’s found a beautiful, near legendary creature, and named it after his dead dog.

The mer seems pleased, though, lips forming the shapes of the letters even though no sound comes out. Yuuri bites his lip, knowing it’s too late to take the name back without causing suspicion, so – the mer becomes Victor, at least for now.

“Victor,” Yuuri repeats, and the mer – Victor – wriggles in the sand, preening with his new, human name. “You’re very pretty.”

Victor starts. He stares at Yuuri for a long moment, but then, a delicate flush colors his pale cheeks, and he looks down almost bashfully. He knocks the remaining seaweed from his head, combing his fingers through his soft, silky hair in a way that seems almost flirtatious.

He has _gills_ , Yuuri realizes, clearly some kind of compound gill and lung system, because the rise and fall of his chest is a feature of land animals.

“I… Hm, I’m wondering if you can answer this,” Yuuri murmurs, “Victor, we almost never see mer on land. What brought you here?”

Victor stiffens, expression crumpling, sadly. He flops his tail, gesturing to his fins, and tucks his long hair behind his ears.

“Oh,” Yuuri breathes, heart panging with a mixture of pity and horror, “Oh. You’re… You’re injured.”

Victor nods, sadly. His fins, like gossamer curtains, are ripped into delicate ribbons. Yuuri imagines how they might be used to propel him through the water, how without them, he simply doesn’t have enough thrust to move, even with the little secondary fins along his side. On Victor's hip, too, there’s a set of three deep gashes, running from his hipbone and ending at a slit just a bit below where Victor’s stomach ends and the fish tail begins.

“Oh, Victor,” Yuuri says, sadly – and to his surprise, Victor falls onto him, burying his face into Yuuri’s stomach. Yuuri pats his bare back, noting now that Victor’s hair is soaked, even though he’s been in the sun for a while.

They stay like that for a while, Yuuri staring at the ribbons of Victor’s fins.

“Maybe… Maybe I could help you?” Yuuri says. “Could I examine you? Where you’re hurt?”

He’s no vet, but he has stitched up his fair share of very aggressive dolphins – so maybe there’s something he can do for Victor. Victor eyes him, curiously, before curling his tail towards Yuuri. The tail tapers off into a point, and the fins are translucent, shimmering like a fine dusting of powder. Yuuri touches one of the ribbons, carefully, and monitors Victor’s face for indications of pain.

They’re… Stretchy. Sturdy like thick sheets of rubber, though they’re thin as rice paper. Yuuri would love to take a sample back to the lab and do molecular analysis on them – the advances to polymer science that could be had with a substance thin as paper but strong enough to propel a quite heavy mer through open ocean make Yuuri’s toes curl in excitement.

But – but, Victor is highly intelligent, capable of communication. Even the dolphins Yuuri studies, with their use of tools and capacity for cruelty, don’t have the faculties that Victor does. This isn’t an animal, it’s a human-like being.

A very attractive human-like being. Yuuri has never been good with attraction – with human interaction in general, and the same rush of awkwardness colors his cheeks at just how close this beautiful, beautiful mer is.

Yuuri presses two of the ribbons together, imagining how the tail fins look, fully formed. Their edges are ragged, thicker than the fins themselves, and rough like scar tissue. The fins clearly healed like this, at least partially, though some of the edges of the injuries seem fresh.

An idea hits him.

“Do you know what stitches are?” Yuuri asks, carefully.

Victor cocks his head to the side, hair falling in a silver curtain over his shoulder. He shakes his head, though it’s clear from his expression the word doesn’t sound friendly. Yuuri supposes it isn’t.

“It’s medical,” Yuuri says, quickly. “If there’s a rip in the skin – or, uh, tail, I suppose – you can use a needle,” he holds his thumb and forefinger a few inches apart and mimes pricking himself, “and stitch it back together.”

Victor goes sheet white – a feat considering how pale he is already – and pushes Yuuri away from him with enough force that it knocks the wind from him. He looks left and right, beating his fist into a rock as the waves lap up against him, a low, alien growl in his throat.

“It’s to heal you,” Yuuri says, thinking, _okay_ , _okay, we’re nowhere near at the point where I can bring up needles. Or anything sharp_. “It works on humans all the time. But… Okay. No stitches. I’m sorry. I don’t want to hurt you.”

He takes a step closer, and Victor’s sharp nails curl around a loose rock. Yuuri freezes, hands coming up in front of him. They stay like that for a long moment, silent except for Victor’s ragged breathing and the lap of the surf. They’ve moved further into the water, Yuuri notes, or perhaps the water has moved closer to them. Victor seems more at ease in the surf, though he still flutters his useless tail in frustration.

 _He’s frustrated,_ Yuuri notes, _frightened by what I just said, and frustrated that he can’t just swim away._

Yuuri hears a scuttling below him and notes a teeny little crab crawling along the rock. Slowly, one hand still up, Yuuri reaches down and picks up the scuttling thing, wincing when it pinches at his fingers.

“Hey,” Yuuri murmurs, holding out the crab, still pinched onto his finger, “Hey. I saw you eating this earlier. Are you still hungry?”

Victor’s pupils go very wide. He eyes Yuuri suspiciously, but inches forward, forward – and snatches the crab from Yuuri’s finger. Yuuri winces as it’s ripped away. Victor pops it into his mouth, and Yuuri stares in awe as he gets a close up of that amazingly strong jaw and those sharp, deadly teeth.

His finger is bleeding a little, so Yuuri sighs and sucks on it, absently. Victor flops along in the inches-deep water, back towards Yuuri, eyes sparkling in concern. He takes Yuuri’s hand and pulls the finger from Yuuri’s mouth. He eyes it curiously, watching as a little bead of blood wells up at the pinched end – and, nodding firmly, takes it into his own mouth.

Yuuri’s eyes go wide and he tries not to yelp, feeling the sharp scrape of teeth against his delicate skin. He half worries that Victor has smelled the blood and that it’s activated some primal, hunger-instinct – but then he feels the wet lap of a tongue, very human like, against the bead, and the teeth pull back so Yuuri can no longer feel the scrape of them.

 _Oh_ , he realizes, _he saw me doing this, and he thinks it’ll help_.

“Can I look at your other injuries?” Yuuri asks, while Victor licks his finger. It’s cute – cat-like, and Yuuri aggressively ignores how the hot, wet tongue makes the heat rise under his collar.

Victor narrows his eyes, so Yuuri continues, “No needles involved! I just want to look.”

After another long pause, Victor relaxes again, flopping down over a rock. This time, Yuuri turns his attention to the gashes on Victor’s hip. They, too, look mostly healed – there are thick lumps of scar tissue over the deep gashes, but when Yuuri touches the scales around the top gash he finds them warmer than the others, finds the tissue around the gash slightly inflamed.

He frowns, touching it, and Victor winces underneath his fingers. Yuuri, in a burst of empathy, takes Victor’s hand, running his thumb along the top of it soothingly. Victor leans his cheek against, it, expression unreadable.

The gashes extend to a slit on Victor’s front, just below a much smaller hole that Yuuri hadn’t noticed from far away. Yuuri traces along the lines, carefully, fingers reaching the edge of the slit. Maybe, maybe, he can gauge how deep the cuts go – and he dips his fingers into the slit.

Victor stiffens, and Yuuri pulls his fingers out – but then Victor takes Yuuri’s other hand, the one he’s not resting his cheek on, and presses them against the slit again.

Yuuri swallows. This entrance is wet, warm. He spreads the slit, just a little, and takes note of how the cuts have cause ragged bumps around its edge. Victor’s breathing sharpens.

“I know it hurts,” Yuuri soothes, fingers running along the inner walls of the slit, over the rough edges of the scars. “I just want to see what kind of help you need. Hm...”

He spreads the slit even wider, and Victor’s pink lips open in a little “o,” a silent cry of something. Yuuri pauses as Victor’s breathing becomes heavier, hot against Yuuri’s thigh. His cheeks are flushed, the flush extending to a pair of fluttering ears, fin-like and the same translucent pearl as his tail.

Yuuri swallows, suddenly nervous. Victor’s eyes turn up to him, and he takes Yuuri’s fingers into his mouth once more. Victor’s expression, the curve of his body – he seems almost… aroused?

Something coats Yuuri’s fingers, inside the slit, thick and viscous – and Yuuri realizes what kind of orifice he’s been playing around in.

He _shrieks,_ squirming away from Victor’s warm, damp body in the waves. Water drips from his shorts, which he hadn’t even realized he’d let soak in the surf, and a whole shiver runs through him as Victor reaches out again, confusion and hurt on his face.

“I’m sorry!” Yuuri cries, dipping his fingers into the salt water to remove the slick coating them. “I’m so sorry! Fuck! I didn’t realize – I didn’t even think, oh my god!”

Victor cocks his head to the side, cheeks still flushed, and presents his body to Yuuri, his own fingers dipping into his slit.

“Stop that!” Yuuri shouts.

Victor pulls his fingers out, contrite, and he curls up with his head on his knees – on the knee-like part of his tail – pouting.

“I didn’t realize I was touching there,” Yuuri whispers. “Are you… Are you really okay with that?”

Victor nods, clearly still confused what the problem is. He mimes pushing Yuuri, bites his lip, then shakes his head, trying to communicate something.

Yuuri ponders for a moment, while Victor repeats the set of motions. Then, growing frustrated, he makes the same signal Yuuri had for pricking himself with the needle, then the pushing signal again.

“You would have pushed me off if you didn’t like it?” Yuuri offers, still embarrassed.

Victor nods, brightly. Then, he grins, and Yuuri sees every one of his very pointy teeth. He makes a biting motion.

Yuuri swallows. “Or bitten me. Good. Uh, good.”

He settles back into the water, and Victor curls up next to him again, nuzzling into Yuuri’s hip and presenting his slit again, batting his eyes, coy.

Yuuri sighs, running his fingers through Victor’s hair – or, trying to, but he realizes his fingers can’t penetrate the thick, wet strands. “I want to heal you,” he says, “Uh. Not that I don’t think you’re attractive, but – I want to focus on healing you. Your hip looks like it needs some attention. Do you – do you understand what I mean?”

Victor pouts even harder than before, but he nods.

“Let me get my backpack,” Yuuri says, nodding to the waterproof pack on the shore, away from the rising tide. “I can put some, uh, some stuff on you.”

Victor lets go, reluctantly, gripping onto the rock as the water rises around him. Yuuri pulls out the first aid kit from the backpack, tossing it further up the shore, beyond where the tide rises to, and wades over to the rock outcropping, clambering on top.

He pulls Victor up, who flops, not unlike a seal, onto the land. It’s a funny image – the graceful, beautiful mer, flopping around like a fish on land. Of course, Yuuri notes, he’s likely usually more graceful, it’s just his fins.

Victor stares in awe at the brightly colored bottles of ointment, the bandages, the rattling bottles of pills.

Yuuri pulls out a tube of Neosporin and says, “This will sting a little, but it should help.”

Victor bites his lip and nods, scrunching his face up as Yuuri slathers on the ointment. It’s difficult, attaching bandages to the slippery scales, but Yuuri manages by wrapping gauze and medical tape all around Victor’s hips, like a belt of a bandage.

“Try to keep out of the water for just a bit,” Yuuri murmurs, “Just so it soaks in.”

Victor nods.

Yuuri pulls out a travel-size bottle of aloe vera and says, “Victor, do your shoulders hurt?”

Victor blinks. He prods at one pink shoulder and winces, slightly. Yuuri rubs a bit of the aloe between his fingers, letting Victor sniff at the greenish goo curiously. This brand has menthol in it, too – so it should help and cool at the same time.

Yuuri rubs the aloe into Victor’s back, across his pink cheeks, and Victor shudders, eyes widening as the cooling menthol kicks in. He grabs the bottle furiously, eyes scanning it for some kind of information, before huffing and handing it back when he remembers he can’t read the English packaging.

“It’s aloe,” Yuuri explains. “Um. A land plant, with another land plant in it that makes it all tingly and cool.”

Victor nods, still gazing at his shoulder with interest.

As they wait for the various gels and ointments to settle in, Victor nuzzles into Yuuri’s stomach, and Yuuri strokes along his head.

“What happened?” Yuuri murmurs, gesturing to the gashes. “Can you make the motion of it?”

Victor frowns. He taps his chin, then pushes his lips together and blows out a rattling, wet sound, like a raspberry, one finger making a circular motion in the air at the same time.

Yuuri blinks. “Uh. Something spinning, making a noise. A motorboat?”

Victor beams and nods, pleased Yuuri caught on so quickly.

“How long ago?”

Victor frowns again, but his eyes shimmer with amusement. Clearly, he likes puzzling out how to communicate with Yuuri, so long as Yuuri asks simple questions.

He holds up five fingers, then points to the sun.

Yuuri puzzles, “Uh. Five suns?”

Victor nods, makes the motion again.

“Five suns, so… You’ve seen the sun five times since?”

Victor nods, hesitantly.

“Five days?” Yuuri says, since it makes the most sense.

Victor nods again, clapping his hands together and grinning broadly. His sharp teeth still scare Yuuri a little, but this smile is happy – sweet and heart-shaped. It doesn’t make Yuuri think Victor could rip out his throat with one bite.

“Huh,” Yuuri says, softly. At least he’s confident it wasn’t _their_ boat, the research boat, that is. They’ve only taken it out once, and that was a week ago. “Victor, is it safe for you here?”

Victor nods.

“Are there predators?”

Victor shakes his head and makes the biting motion again.

“So you’re the apex predator here,” Yuuri laughs, fond, “Do you have enough to eat?”

Victor nods again, flushing and smiling, softly. As if to illustrate, he rips a barnacle off the rock with his sharp nails, and crunches it, shell and all, with the same ease he crunched the crab. Yuuri swallows down the shudder that creeps up his spine at that.

Yuuri returns the first aid kit to a place far above the rising tide, then settles in next to Victor. They stay there like that for a while, Yuuri monitoring the rising tide. It’s not such a dramatic change, just covering some of the shorter clusters of boulders, and his backpack is safe. His notebook, not so much – but luckily he makes a point of digitizing everything before he goes to bed, and so the quick notes on Victor are the only thing completely lost.

Victor wriggles as the water lifts his body up, coming in closer to Yuuri.

“How long can you stay out of the water?” Yuuri asks.

Victor puts his hands in front of his chest and spreads them apart.

“A long time?” Yuuri interprets, and Victor nods again.

Victor wriggles again, and Yuuri catches the scent of aloe clinging to him. His hair is still wet, though he’s spent most of the day with his head above water – perhaps it’s more like a seal’s coat, trapping in heat so it doesn’t escape through his scalp.

Then, Victor grabs Yuuri’s hand and brings it down to his slit again, pressing it there insistently.

Yuuri goes bright red. “Victor,” he whines, trying to pull his hand away, “I don’t – humans don’t usually have sex right after meeting someone! And I feel bad, that was an accident before!” He mutters, “Can’t believe I didn’t realize that’s what that was.”

Victor pouts, wrapping his arms around Yuuri’s shoulders and lifting himself up. His lips brush against Yuuri’s and Yuuri could swear he’s mouthing the word _please_.

“Why do you want me?” Yuuri sighs. “Is this normal for your kind, presenting yourself right once you meet someone?”

Victor sighs and shrugs. He gestures to the bandages on his hip, to his tail fins, which flutter uselessly in the water.

“You want to because I helped you?” Yuuri asks in disbelief. “Victor… You don’t have to give me anything. I’ll help you for free.”

Victor’s eyes go wide and he puts his hand over his heart, clearly touched. Then, he taps his chin, thoughtfully.

“Victor,” Yuuri teases, as Victor continues to preen, “You’re very, very confident that I want you, aren’t you? It’s never occurred to you that I might not?”

Victor snorts as if the idea is laughable to him, proudly tossing his silver hair over his shoulder. Then, he freezes, and his eyes go very wide, his lips all pouty and trembly. He grabs Yuuri’s hand ask if to ask, _wait, you don’t?_

Yuuri can’t help but laugh at his vanity. Victor pouts even harder.

“It’s not that I _don’t_ ,” Yuuri sighs, and Victor’s pout disappears almost instantly. “Well, I just…”

Yuuri wonders what his hesitation is. He’s had sex with less pretty people with even less interaction than this, so what’s holding him back from giving Victor what he so clearly wants? Is it because, despite his good looks, he’s clearly not human? That Yuuri has no idea what to do, what even feels good?

He settles on, “It’s not like sleeping with a person. I don’t want… I don’t want to hurt you, if this means something to mer that it doesn’t to a human.”

Victor whines, a strange, alien sound. Something thrums through Yuuri, hot and desperate. He hasn’t had sex in so long, not since they got to the island, not since long before that, too. The fact that Victor isn’t human, though – it tugs at him, makes him hesitate.

As Yuuri frets, Victor nudges at him. He smiles, wickedly, and points to something farther up the beach.

Yuuri follows his gaze, nudging his glasses further up his nose. There’s the edge of the shore, the path leading back up to their research base… He frowns, looking to Victor in confusion.

Victor rolls his eyes and points harder, so Yuuri looks harder – and sees his notebook, soaked through and bobbing in the water.

“My notebook?” Yuuri questions, still confused.

Victor nods, pointing at the notebook, then running his hand seductively down his chest, fingers playing over the edges of his slit – mating slit, Yuuri realizes.

“Notebook, your body...” Yuuri murmurs, not quite getting it.

Victor’s expression grows frustrated. He mimes making notes, then dips his fingers inside himself, then places Yuuri’s hand at his mating slit.

It clicks into place.

“You want me to… To take notes?” Yuuri squeaks.

Victor nods, triumphantly.

“But – but the notebook is all wet,” Yuuri says, pathetically.

Victor rolls his eyes and taps Yuuri’s forehead.

“Oh, uh, oh,” Yuuri stammers, “Right, I could… Write everything down after.”

Yuuri sits back, legs spread in the water. His hiking boots are soaked, his shorts are soaked. Victor smirks and settles between his legs, his back pressed to Yuuri’s clothed chest.

Fuck. Victor’s got him. All the excuses he’s been making for not touching him, even though he wants to – but mer reproduction is a complete unknown, and Victor, bright and curious and incredibly perceptive, had noticed how many questions he asked, how he had been taking notes before…

Yuuri swallows. He asks, voice embarrassingly high-pitched, “You’re sure you want this? Me? We’re not even the same species!”

Victor shoots him a withering look from over his shoulder.

Yuuri says, “Uh. Right. Well, okay, here I go...”

Then immediately wants to bury his head in the sand. They’re up on a different rock formation, hopping from one to another throughout the course of the afternoon, all but Victor’s tail-fins out of the water, glistening like pearls in the sun.

He takes a deep breath and runs his fingers along the outside of Victor’s mating slit, avoiding the bandages. It twitches, opening just a little, and Victor’s breath hitches.

Yuuri takes his other hand and wraps it under Victor’s armpit, brings it to his throat. Victor swallows as Yuuri massages, gently – it’s completely smooth, not ribbed like a human throat. No vocal chords, clearly, the body needing to accommodate for the fluttering gills running up the sides. Yuuri runs his finger along them and Victor shudders.

“Here,” he murmurs, pressing a finger against Victor’s mouth. “Nibble if I’m doing something you don’t like. Uh, please don’t bite, though.”

Victor smirks against the finger, kissing it softly.

Yuuri dips two fingers into Victor’s mating slit, aware of how little he knows. It’s slick, warm, and the walls contract around the fingers. He probes around the walls, making little stroking motions on all sides of them, and Victor tosses his head back into the crook of Yuuri’s neck, lips parted in a silent cry.

Is there… Is there something like a g-spot in here? Or should he be searching for something more like a bundle of nerves poking out from the flesh? Will tentacles start popping up out of nowhere? Yuuri bites his lip, continuing to stroke.

Victor’s getting wetter, which is a good sign, and Yuuri scissors his fingers in the wet slit. Victor pants, but not particularly harder than he was at the strokes along his walls.

Yuuri frowns, rubbing his thumb at the hole above the slit – and feels a little nibble on his finger. Ah, he thinks, removing his thumb immediately. Not something Victor wants to be touched.

The walls inside the mating slit seem to expand, and Yuuri finds he can slip in three fingers with ease, now, spreading them apart and snapping them back together. His thumb goes around the edges of the slit, which swell and slicken at the contact, and Yuuri knows he’s hitting a sweet spot when Victor tosses his head back, eyes screwed shut.

So, the edges of the slit are more sensitive than the walls, and Yuuri croons, “Do you like it there?”

Victor nods, desperately, and Yuuri removes his fingers from inside to stroke up the edges of the slit, now swollen and puffy with arousal. The slit isn’t just a slit, now, it looks like wet, swollen lips, dripping slick and contracting around Yuuri’s fingers.

Yuuri can’t help but wonder if he’s gotten Victor’s gender wrong – but that’s a question for another time.

“Do you have a more sensitive spot?” Yuuri asks, still stroking up and down the puffy slit, which is now dripping slick profusely.

Victor nods, about to reach for it, but Yuuri grabs his hand.

“Wait,” Yuuri murmurs, letting go of the hand to continues stroking the slit, fingers dipping back inside. “I’m a scientist, you know? I want to find it for myself. Am I close?”

Victor nods again. His eyes are glazed over, his chest heaves, and his mouth is open with Yuuri’s fingers inside it, drool dripping down his chin.

He still looks beautiful like this, Yuuri thinks, and he kisses Victor’s cheek. Watching Victor, the way he writhes and wriggles under Yuuri’s ministrations – it’s hot, so unbelievably hot. Heat pools in Yuuri’s belly, and he bites his lip as he feels himself getting hard.

 _Is it weird that I’m getting off on this?_ Yuuri wonders, _he’s not so different from a human – and it’s not like I have a preference for human genitalia. He said – he said this is for research, and this is important research. Really important._

_I can fudge the “experimental methods” section of the resulting research paper._

Yuuri frowns. Victor’s walls feel slightly different than before – there’s a bigger, vein-like thing running along the top of the slit, and Yuuri strokes one finger along it, experimentally.

Victor _writhes_ , flushed down to his chest, and Yuuri thinks, _there it is._

“Mm, did I find it?” Yuuri teases, purposely avoiding the thick… Whatever it is.

Victor nods, whimpering voicelessly, thrusting his hips up so Yuuri’s fingers plunge deeper into him. Yuuri laughs, stroking _experimentally_ along the vein, trying hard to pin Victor in place as he writhes. It ends in a little nub, and when Yuuri flicks it, Victor’s eyes fly open and his lips part in a wordless scream.

 _Huh_ , Yuuri thinks, running slow circles around the nub and watching Victor’s back arch with pleasure, _this is far closer to – well, it’s important data, at least._

Yuuri’s cock twitches into Victor’s naked back, the dampness of his shorts lessening the dampness of precum a little bit. _Important data,_ he snorts, biting his lip. He’s kidding himself at this point.

He wonders how mer do this – wonders if mer put their mouths on each other. He wonders so much, and he resumes stroking the puffy folds of Victor’s slit, rubbing slow circles around the bud at the same time. He strokes the slick folds and the swell of the vein and nub, wondering if mer orgasm like humans do – when suddenly Victor’s entire body is shaking and slick is pouring out of him, coating Yuuri’s fingers.

 _That answers that question_ , Yuuri supposes.

Yuuri continues to stroke, feeling the contractions from the slit, the little nub jerking and twitching. Finally, Victor settles back against Yuuri’s chest, panting – and Yuuri removes his fingers, washing away the slick in the salt water.

His slit is still swollen, and when Yuuri touches it, Victor gasps and bats Yuuri’s hand away.

Yuuri kisses Victor’s cheek, apologetic, and Victor slumps against him.

Fuck, he’s so hard. Yuuri needs to go back, hopefully before Phichit and Celestino return from their own research, and spend a nice long time in the shower.

The sun is beginning to set, casting a golden glow over the beach.

Victor pouts, wrapping his arms around Yuuri’s waist and nuzzling into his stomach. Yuuri winces at his hardness tenting his pants – and finds Victor staring at it, curiously. He pokes it.

Yuuri gasps, flushing, and Victor looks up at him, surprised. He puts his palm over the tent, feeling the outline of Yuuri’s hard cock, and his eyes go very, very wide.

He grabs the hem of Yuuri’s shorts and attempts to yank them down.

Yuuri yelps, holding them up, and says, “V-Victor! What are you doing?”

Victor points at his hard cock in his shorts, almost accusatory, then points back at his slit.

Yuuri blinks. “Did you… Not know that was in there?”

Victor shakes his head, putting his hands on his cheeks like Yuuri has turned his whole world inside out.

“Humans wear clothes,” Yuuri explains, bemused. “Like, coverings. To protect from the – the harsh land elements. And hide our… Uh. Reproductive organs.”

Victor looks incredulous at that.

“I guess it is kind of silly if you think about it – hey!” Yuuri nudges away Victor’s hand when it reaches out to grab him again.

Victor pouts – oh, that pout will be the death of him, Yuuri knows – Yuuri cups Victor’s cheek, kissing it, softly. “Alright, alright. You surprised me, is all. I really, hah,” Victor doesn’t wait for him to finish, fingers grabbing all around his hard cock, pumping up and down, “Hah – wait, my clothes...”

Victor watches in amazement as Yuuri pulls off every layer of clothing, his shoes, his socks, his shorts, his shirt, his hat… He leafs through them, holding up Yuuri’s briefs, curiously. He cocks his head to the side as if to ask, _why_?

Yuuri swallows, a shiver running through him, as Victor seems transfixed by the now folded up piles of cloth.

“Hah, I take my clothes off, and suddenly they’re more interesting than I am,” Yuuri teases, patting Victor’s head. The hard rock digs into his bare skin, but he ignores it as Victor turns back to him.

Victor stares between his legs, lifting up his hard cock. He pokes at Yuuri’s balls curiously, and Yuuri winces as his sharp nails prod at his most sensitive areas.

“Hurts,” he murmurs, and Victor pulls his nails away immediately. “Um, we don’t usually – poking doesn’t usually feel good. You can try massaging?”

Victor cups Yuuri’s balls, eyeing them curiously, massaging them with surprising gentleness. Then, he points to Yuuri’s cock, points back to his slit.

“Um,” Yuuri murmurs, “What are you…?”

Victor lies back on the rock, gently guiding Yuuri on top of him, and Yuuri straddles his waist, leaking cock pressing against the slit. He adjusts, being especially careful not to rub against the bandages, though he could feel the thick scar tissue inside Victor as he fingered him.

“Ah,” Yuuri murmurs. “You want to go again?”

Victor nods, eagerly, and his hands go to his stomach.

Yuuri runs the length of his cock along the edges of the slit, watching them swell again, letting Victor’s slick soak his length. Victor’s fingers go to his lips, his cheeks flush deep red in the sunset. He reaches down to massage Yuuri’s balls again, head cocking to the side.

“Mer don’t have those, I suppose?” Yuuri asks. Victor shakes his head. “It seems… It seems you’re learning a lot about me, as well.”

Victor nods, grinning, releasing Yuuri’s balls to grab the firm globes of Yuuri’s ass.

“Do some of you have these?” Yuuri asks curiously, gesturing to his length.

Victor taps his chin and nods, hesitantly. Yuuri has more questions – so many more – but his cock is throbbing at the feel of Victor’s wet slit around it, and he can’t seem to remember them at the moment.

Yuuri positions his cock at Victor’s entrance, wet and hot, and stares at Victor’s face as he steadily presses the tip into his swollen folds. Victor gasps, his walls tugging at Yuuri’s cock, the viscous slick almost sticky to encourage Yuuri to stay in.

He inches inside, feeling the suction from Victor’s walls, pushing in until he’s fully sheathed and his balls press against the entrance to the slit. Victor tosses his head back in pleasure, flushed down to his chest, and from this angle Yuuri can admire how arousal tinges his cheeks, how he looks so blissed-out with Yuuri inside him.

Yuuri pulls his cock out, still straddling Victor, and thrusts it back, deep inside.

Victor’s eyes fly open and his nails _clench_ into Yuuri’s skin, and Yuuri yelps, the pain almost drowning out the pleasure of Victor’s wetness sucking on his cock.

“Nails,” Yuuri gasps, “Nails… Sharp.”

Victor unclenches his hand immediately, bringing it to his lips. His eyes glitter apologetically, and Yuuri could swear he mouths the word _sorry_.

Yuuri breathes a sigh of relief, brushing a strand of hair from Victor’s forehead and kissing him there as if to say, _all is forgiven_.

Then he thrusts in again and Victor screws his eyes shut, lips parting.

Yuuri feels the sensitive organ at the top of Victor’s slit along the length of his cock, so he adjusts his position to slide his cock along it, feeling the tip pressed hard against it as he thrusts in and out.

Victor’s eyes are open again, his cheeks flushed, his lips parted in a little, adoring smile as he stares at Yuuri – and Yuuri almost freezes, caught off guard by how tender he looks, even with the edges of his sharp teeth peeking out from beneath his lips.

He’s getting wet again, slick coating Yuuri’s cock, and Yuuri is amazed he’s been able to last this long with the walls sucking at him and his balls pressed to Victor’s slit and Victor _looking_ at him like this. He flushes, burying his face in Victor’s neck, suckling at it gently. He can hear little rushes of air from Victor’s gills, and he runs his fingers along them, carefully.

Yuuri spreads his legs where he’s straddling Victor, thrusting deeper, the tip of his cock pressing against something deep inside him that his fingers couldn’t reach. Victor gasps as Yuuri hits it, angling his hips so Yuuri is rubbing up against it with every thrust. Then, Victor clenches, slit once again leaking slick, walls contracting around Yuuri’s cock, the organ at the top of the slit shuddering and jerking-

And Yuuri tumbles over the edge himself, crying out as the suction of Victor’s walls brings his orgasm crashing over him, and hot cum spurts out of his cock and into Victor, his slit drinking it in greedily.

They stay like that for a while, Yuuri’s face buried in Victor’s neck, both gasping for breath. Eventually, shuddering, Yuuri pulls his softening cock out of Victor’s slit, a strand of slick and come between the two of them.

Nothing leaks out of Victor, though, and Yuuri stares at his swollen slit with interest – clearly a mechanism designed to keep come inside, a sort of natural plug. Sure enough, when Yuuri reaches towards it, Victor slaps his hand away none too gently, scowling.

Instead, Yuuri adjusts the bandages, makes sure they’re still on tight. The neosporin has likely soaked in at this point, and the salt water will be a good disinfectant, but it doesn’t hurt to protect the area.

“Victor,” Yuuri finds himself asking, “Are you male or female?”

Victor cocks his head to the side, as though he doesn’t understand the question.

“Uh,” Yuuri pauses, realizing he’s at a loss for how to explain male and female. “Can you… Can you get pregnant?”

Victor freezes. He looks stricken by the question, and Yuuri immediately wants to take it back – but before he can, Victor shakes his head, not meeting Yuuri’s gaze.

Yuuri doesn’t ask anything more, thinking he’s gotten the gist of Victor’s answer. Victor’s hands lie on his stomach, his expression troubled, and Yuuri nudges them aside to press a soft kiss to Victor’s navel.

“It’s alright,” Yuuri says, softly. “I think you’re perfect.”

Victor offers him a wobbly smile, and Yuuri flops onto his back, shoulder to shoulder with Victor, taking his hand in his. Victor stares at that curiously, but he doesn’t pull his hand out of Yuuri’s grip.

He’s always rushed into things. His parents always told him that – but this, what he’s just done, is on an entirely different level.

 _Gathering data_.

Yuuri supposes he can’t pretend his interest in Victor is purely academic. He’s never felt so much attraction to someone so quickly – somehow he’s not questioning the fact that it happened with someone non human. Seduced by the mer is a common feature of old folktales, after all, though Yuuri somehow doubts this evening will end with him being eaten.

Victor, sharp teeth and sharp nails and all, looks so soft as he lies there, nuzzling his wet head into the crook of Yuuri’s neck.

They lie naked on the rocks, watching the sun slowly sink beneath the horizon. Yuuri knows he’ll have to go back at some point – wade in the knee-deep water back to shore, but for now he lets his thoughts collect. He stares at his knees, scratched and bloody from kneeling on the rocks over Victor, and frowns. Victor seems to notice too - he shifts, so his face is in front of the scrapes, and licks up along them until the blood is mostly gone. 

Yuuri realizes he hadn't properly seen Victor's tongue until that moment. It's long, far longer than a human tongue, tinged blue and tapered into an almost reptilian point. Not for the first time it hits him that Victor really isn't human. 

"Does my blood taste good?" Yuuri asks, cautiously. 

Victor scrunches up his face and shakes his head. He points to Yuuri's hand, then puts one finger in his mouth, and Yuuri realizes with a rush of fondness that Victor really thinks licking injuries helps them heal. He doesn't quite have the heart to tell Victor that's not the case, and anyway, Victor licking his knees is more than a little weird. Victor looks so proud of himself as he snuggles back up next to Yuuri, and Yuuri has a sudden vision of that strange tongue licking his cock, lapping up and down-

He gulps and tries to ignore the thought, at least for now. 

The waves lap against the ribbons of Victor’s tail, and Yuuri supposes his next task is convincing Victor that stitches will fix them, at least hopefully.

Victor is so, so beautiful. He must be very lonely if he’s chosen plain Yuuri to mate with.

Yuuri knows he isn’t anything special, just a simple marine biologist – but if he can somehow help this wonderful mer, it will be enough, he thinks.

It’s going to be an interesting summer.

**Author's Note:**

> And then Yuuri fixes Victor's tail and then they live happily ever after.
> 
> Notes on mer!
> 
> Lol Victor has no concept of your weird human genders. I basically see them as being born intersex (ie with both a penis like thing and a vagina like thing) and then when they reach sexual maturity and find a mate one becomes an "alpha" where the penis like thing gets bigger and sperm production begins and the vagina like thing gets smaller and the other becomes an omega where the penis like thing just kinda... falls off. I've seen some worldbuilding with mer where the penis thing gets ripped off by the alpha but that's not super my jam so I just have it fall off.
> 
> I had a whole backstory in my head where Victor (who is an omega in this, y'all know I love my omegas) had a previous mate who abandoned him after many unsuccessful years of trying to get pregnant, assuming that Victor was infertile. That didn't manage to make it in, just Victor being upset that he may be infertile, but there you go.


End file.
